Apparatus for freezing foodstuffs



July 20, 1943. D, w, KlNG 2,324,517

APPARATUS FOR FREEZING FooDsTUFFs Filed April l, 1942 2 Sheets-Sheet l@6v/'0' W/f/'ng INVENTOR AT'oRNEY July 20, 1943- D. w. KING APPARATUSFOR FREEZING FOODSTUFFS Eiled April l, 1942 2 Sheets-Shea?l 2 |NvENToRBY MRM ATTORNEY Patented July 20, 1943 UNITED STATESr PATENT OFFICE'.

APPARATUS Fon FnEEzmG FooDs'rUFrs David W. King, Knoxville, Tenn.Application' April 1, 1942, serial No. 437,285

(Cl. sz-104) (Granted under the t of March a, 1883, as amended April30,'1928; 370 0. G. 757) l Claim.

The invention herein described may be manufactured and used by or forthe Government for governmental purposes without the payment to me ofany royalty thereon.

This invention relates to the art of freezing foodstuff, particularlythe individual quick freezing'of such foodstuff. f

Units of foodstuff have been individually fro-` zen by bringing them indirect contact with a refrigerant fluid, but it is often desirable ornecessary to remove refrigerant fluid which remains adhered to thefrozen foodstuff before the same is packaged for distribution. Oneprocess has been proposed which indicates that this particulardiillculty might be substantially overcome, wherein the units of acomestible are enclosed with a highly flexible material having thecharacteristic of being able to conform at low temperaturessubstantially to the shape of the comestible confronting the material,the comestible being frozen by means of refrigerant ypassing in contactwith such flexible material.

The principal object of this invention is to provide an apparatuswherein units of a comestible may be individually frozen by continuousmovement through a zone cooled by refrigerant liquid without retainingany appreciable portion of such liquid on `the surface thereof. Anotherobject of this invention is to provide an apparatus for the quickfreezing of comestibles wherein such `co mestibles are frozen by thermaltransfer through a semipermeable membrane, thereby preventing theretention of any apprecla eamount of refrigerant on the surface thereof.A further object of this invention is to provide an apparatus i forfreezing foodstuff which will transfer heat readily 1n a zoneimmediately adjacent to the product being frozen due to the capability'of cerf tain elements thereof to'readily conform to the shape of unitsof the material being frozen. A still further object of this inventionis to provide an apparatus forthe quick freezing of comestibles which isreadily adjustable to accommodate the character and size of variouscomestibles which may be frozen therein. Still another object of thisinvention is to provide an apparatus for the quick freezing of foodstuffwherein the refrigerant liquid is not appreciably contaminated byconstituents or components of the foodstuff being frozen. Other objectsof this invention include the provision of an apparatus for freezingfoodstu which is economical to construct, which may be built inrelatively small units, and which has a relatively high capacity.

'I'he present invention is directed to an apparaflexible material ofsaid first and second mobile.

members; means for disposing units of comestible on said first mentionedmobile member; and means for moving said mobile members and the units ofcomestible between them through said chamber whereby said units arefrozen by thermal transfer through said flexible material.

In the accompanying drawings which form a part of the specification,wherein reference sym- `bols refer to like parts whenever they occur,

Fig. 1 is a sectional, longitudinal, elevational view of one form ofapparatus for the embodiment of the present invention; and

Fig. 2 is an enlarged,`transverse, elevational view of section 2-2 ofthe apparatus shown in Fig. 1.

In the drawings, units of the comestible I to be frozen are deliveredfrom feed table 3 to moving mobile member E which is composed of alaterally supported sheet I of highly flexible material having thecharacteristic of being able to conform at low temperaturessubstantially to the shape of units of a comestible contacting the same,the supports therefor consisting of flexible metal cables 9 over drivensheaves Il. The cables 9 are so spaced that the sheet I is formed into apredetermined configuration whenthe units of comestible come in contacttherewith. As the units of the comestible proceed along the mobilemember 5 they are confronted with a second mobile member I3 composed ofa like sheet of highly flexible material I5, which is laterallysupported, such lateral supports consisting of attachments I1 connectedto an endless chain I3 which passes over drivensprocket '2,I andj idlesprocket 23. The refrigerant liquid in reservoir 25 is maintained atvtheproper temperature by refrigerating coils 21 of a refrigerationapparatus (not shown). The refrigerant liquid so cooled is delivered bypump 29 through conduit 3l to an equalizing pressure reservoir 33 anddelivered through conduit 35, to headers 31 and 39 located respectivelyabove mobile member I3 and below mobile member 5. Each header isprovided with conduits 4I, each of which are equipped with spray nozzles43, which direct the refrigerant liquid downwardly and upwardlyrespectively on the sheets I5 and 1 of the highly flexible material. Theedges of each supported sheet of highly flexible material 1 and I5 areprovided with aprons 45, which by falling in close juxtaposition as themobile members of which they are a part pass through the spray ofrefrigerant liquid form a seal which prevents the refrigerant liquidfrom coming in direct contact with the units of the comestible as theypass through the refrigeration zone. The units of the comestible arepassed along by the mobile members 5 and I3 at such a rate that they arefrozen to the desired degree and are thereafter discharged from mobilemember 5 into discharge chute 41.

The essential feature of the present invention isto provide an apparatuswherein units of a comestible are moved continuously between two sheetsof highly flexible material having the characteristic of being able toconform at low temperatures substantially to the shape of the units ofthe comestible confronting the same. Such material may eitherbeimpervious to refrigerant liquid or slightly liquid permeable. Thefiexible sheets of material so contacting the units of the comestibleconform thereto, regardless of'variation in sizes of the units of anyone comestible. The sheets of exible material may be impervious to theliquid refrigerant, particularly where such ing the upper forward sheaveor sprocket, the lower forward sheave or sprocket, or both sheaves orsprockets. Ordinarily. the speed 'of the through' the refrigerationzone. thereby presenting a changing relationshipfbetween the surface ofthe units of the comestible and the surface oi' the highly flexiblesheets of the respective mobile members.

refrigerant is not particularly suitable for direct contact with thecomestible, but it is preferable that the flexible material be semiliquid permeable; that is, it will have the characteristic of being ableto be wet by the refrigerant, and thereby afford a more rapidthermaltransfer between the units of the comestible and the refrigerantliquid. An unfilled canvas is a typical example of a exible materialwhich is only semi liquid permeable --and which has been found to besatisfactory for .covering the units of the comestible being frozen is`laterally supported by cables or chains suspended between sheaves orsprockets, while the intermediate portions thereof are supported by theupper surfaces of the units of the comestible in contact therewith- Themobile members comprising the lowerv highly flexible sheet and the upperhighly fiexible sheet and the corresponding lateral supports and sheavesor sprockets attached thereto may be moved through the refrigerationzone, by rotat- The refrigerant liquid used for the freezing of theunits of the comestible is directed upwardly against the bottom of thehighly flexible material of the lower mobile member upon which the umtslof the comestible being. frozen are supported, and

it is likewise directed downwardly upon thefsurface ofthe upper layer ofthe highly flexible material of the upper mobile member which covers theunits of the comestible being frozen. The refrigerant liquid passes fromthe' highly flexible sheet and is returned to the refrigeration systemfor further cooling and recycling. The edges of the upper sheet, andpreferably the edges of both sheets of the highly flexible material ofeach mobile member are provided with flexible aprons which, by fallingin close juxtaposition as they pass through said zone. seal the units ofthe comestible passing through said zone against the admission ofrefrigerant` liquid, either in the form of a spray as it is applied tothe surfaces of the highly flexible material. or as a liquid stream asit flows from the surface of the upper sheet of such material.

It will be seen, therefore, that this invention actually may be carriedout by the use of various modifications and changes without departingfrom its spirit and scope.

I claim:

An apparatus for freezing units of a comestible which comprises thecombination of a chamber providing a refrigeration zone; a' mobilemember traversing said chamber, said member comprising a laterallysupported sheet of highly flexible material having the characteristic ofbeing able to conform at low temperatures substantially to the shape ofunits of comestible contacting the same; a second like^mobi1e membermoving contiguous to and above said first mentioned mobile member; meansfor directing refrigerant liquid against the bottom and top,respectively, of the flexible material of said first and second mobilemembers; means forfdisposing units 0f comestible on said first mentionedmobile member; and means for progressing said mobile members moving atdifferent rates and the units of comestible between them through saidchamber, thereby causing a change of surface contact of units ofcomestible disposed between the flexible material of said mobile memberswith the freezing of the comestible units by thermal transfer throughsaid exible material.

DAVID W. KING.

